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Author (up) Colloca, L.; Benedetti, F. file  url
doi  openurl
  Title How prior experience shapes placebo analgesia Type Journal Article
  Year 2006 Publication Pain Abbreviated Journal Pain  
  Volume 124 Issue 1-2 Pages 126-133  
  Keywords Adult; Analgesia/methods; Analysis of Variance; Child; Electroshock/adverse effects; Female; Humans; Male; Pain/*drug therapy/etiology/physiopathology/*psychology; Pain Measurement/methods/psychology; Pain Threshold/drug effects; *Placebo Effect; Placebos/*therapeutic use  
  Abstract Some studies indicate that placebo analgesia is stronger when pre-conditioning with effective analgesic treatments is performed, thereby suggesting that the placebo response is a learning phenomenon. Here we further tested this hypothesis in order to better understand when and how previous experience affects the placebo analgesic response. To do this, we used a conditioning procedure whereby the intensity of painful stimulation was reduced surreptitiously, so as to make the subjects believe that an analgesic treatment was effective. This procedure induced strong placebo responses after minutes, and these responses, albeit reduced, lasted up to 4-7 days. In addition, in a second group of subjects we repeated the same conditioning procedure 4-7 days after a totally ineffective analgesic treatment, and found that the placebo responses were remarkably reduced compared to the first group. Thus we obtained small, medium and large placebo responses, depending on several factors, such as the previous positive or negative experience of an analgesic treatment and the time lag between the treatment and the placebo responses. We also ran extinction trials, and found that these effects did not undergo extinction in a time span of several minutes. These findings indicate that placebo analgesia is finely tuned by prior experience and these effects may last, albeit reduced, several days. These results emphasize that the placebo effect is a learning phenomenon in which many factors come into play, and may explain the large variability of the placebo responses that is found in many studies.  
  Call Number Serial 205  
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Author (up) Eippert, F.; Bingel, U.; Schoell, E.D.; Yacubian, J.; Klinger, R.; Lorenz, J.; Buchel, C. file  url
doi  openurl
  Title Activation of the opioidergic descending pain control system underlies placebo analgesia Type Journal Article
  Year 2009 Publication Neuron Abbreviated Journal Neuron  
  Volume 63 Issue 4 Pages 533-543  
  Keywords Adult; Analgesia/*methods; Analgesics, Opioid/pharmacology/therapeutic use; Double-Blind Method; Humans; Male; Naloxone/pharmacology/therapeutic use; Pain/*physiopathology/prevention & control; Pain Measurement/drug effects/*methods; Placebo Effect; Pyramidal Tracts/drug effects/*physiology; Receptors, Opioid/*physiology; Signal Transduction/drug effects/physiology; Young Adult  
  Abstract Placebo analgesia involves the endogenous opioid system, as administration of the opioid antagonist naloxone decreases placebo analgesia. To investigate the opioidergic mechanisms that underlie placebo analgesia, we combined naloxone administration with functional magnetic resonance imaging. Naloxone reduced both behavioral and neural placebo effects as well as placebo-induced responses in pain-modulatory cortical structures, such as the rostral anterior cingulate cortex (rACC). In a brainstem-specific analysis, we observed a similar naloxone modulation of placebo-induced responses in key structures of the descending pain control system, including the hypothalamus, the periaqueductal gray (PAG), and the rostral ventromedial medulla (RVM). Most importantly, naloxone abolished placebo-induced coupling between rACC and PAG, which predicted both neural and behavioral placebo effects as well as activation of the RVM. These findings show that opioidergic signaling in pain-modulating areas and the projections to downstream effectors of the descending pain control system are crucially important for placebo analgesia.  
  Call Number Serial 244  
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Author (up) Haour, F. file  url
  Title [Mechanisms of placebo effect and of conditioning: neurobiological data in human and animals] Type Journal Article
  Year 2005 Publication Medecine Sciences : M/S Abbreviated Journal Med Sci (Paris)  
  Volume 21 Issue 3 Pages 315-319  
  Keywords Animals; *Conditioning (Psychology); Humans; *Placebo Effect  
  Abstract A placebo is a sham treatment such as pill, liquid, injection, devoid of biological activity and used in pharmacology as a control for the activity of a drug. In many cases, this placebo induces biological or psychological effects in the human. Two theories have been proposed to explain the placebo effect: the conditioning theory which states that the placebo effect is a conditioned response, and the mentalistic theory for which the patient expectation is the primary basis of the placebo effect. The mechanisms involved in these processes are beginning to be understood through new techniques of investigation in neuroscience. Dopamine and endorphins have been clearly involved as mediators of the placebo effect. Brain imaging has demonstrated that the placebo effect activates the brain similarly as the active drug and in the same brain area. This is the case for a dopamine placebo in the Parkinson'disease, for analgesic-caffeine- or antidepressor-placebo in the healthy subject. It remains to be understood how conditioning and expectancy are able to activate, in the brain, memory loops that reproduce the expected biological response.  
  Call Number Serial 1782  
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Author (up) Neumann, M.; Edelhauser, F.; Kreps, G.L.; Scheffer, C.; Lutz, G.; Tauschel, D.; Visser, A. file  url
doi  openurl
  Title Can patient-provider interaction increase the effectiveness of medical treatment or even substitute it?--an exploration on why and how to study the specific effect of the provider Type Journal Article
  Year 2010 Publication Patient Education and Counseling Abbreviated Journal Patient Educ Couns  
  Volume 80 Issue 3 Pages 307-314  
  Keywords *Communication; Conditioning (Psychology); Evidence-Based Practice; Humans; *Outcome Assessment (Health Care); *Physician-Patient Relations; *Placebo Effect; Randomized Controlled Trials as Topic  
  Abstract OBJECTIVE: Numerous studies demonstrate the impact of high-quality patient-provider interaction (PPI) on health outcomes. However, transformation of these findings into clinical practice is still a crucial problem. One reason might be that health communication research rarely investigated whether PPI can increase the effectiveness of medical treatment and/or even substitute it. Therefore, our objective was to provide empirical and methodological background of why and how to investigate the specific effect of the provider on patients' health outcomes. METHODS: This is a debate paper based on a narrative (non-systematic) literature review in Medline and PsycINFO without any year limitation. RESULTS: Neurobiological evidence based on expectation and conditioning theory indicates that PPI is able to increase the effectiveness of medical treatment. Moreover, the use of creative RCT study designs described in this paper enables health communication researchers to investigate whether PPI is able to substitute medical treatment. CONCLUSION: This paper exemplifies that there exist an evidence-based knowledge from neurobiology as well as creative RCT designs which enable researcher to investigate the specific effects of PPI. PRACTICE IMPLICATIONS: Research on the specific effects of PPI requires intense reflection on which patient groups or types of illness are reasonable, suitable, and ethically justifiable for interventions.  
  Call Number Serial 401  
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Author (up) Price, D.D.; Milling, L.S.; Kirsch, I.; Duff, A.; Montgomery, G.H.; Nicholls, S.S. file  url
  Title An analysis of factors that contribute to the magnitude of placebo analgesia in an experimental paradigm Type Journal Article
  Year 1999 Publication Pain Abbreviated Journal Pain  
  Volume 83 Issue 2 Pages 147-156  
  Keywords Administration, Topical; Adult; Affect; Analgesics/administration & dosage/*therapeutic use; Conditioning (Psychology); Female; Forearm; Humans; Male; Pain/drug therapy/*physiopathology/psychology; Pain Measurement; *Placebo Effect; Skin Temperature  
  Abstract Placebo analgesia was produced by conditioning trials wherein heat induced experimental pain was surreptitiously reduced in order to test psychological factors of expectancy and desire for pain reduction as possible mediators of placebo analgesia. The magnitudes of placebo effects were assessed after these conditioning trials and during trials wherein stimulus intensities were reestablished to original baseline levels. In addition, analyses were made of the influence of these psychological factors on concurrently assessed pain and remembered pain intensities. Statistically reliable placebo effects on sensory and affective measures of pain were graded according to the extent of surreptitious lowering of stimulus strength during the manipulation trials, consistent with conditioning. However, all of these effects were strongly associated with expectancy but not desire for relief. These results show that although conditioning may be sufficient for placebo analgesia, it is likely to be mediated by expectancy. The results further demonstrated that placebo effects based on remembered pain were 3 to 4 times greater than those based on concurrently assessed placebo effects, primarily because baseline pain was remembered as being much more intense than it actually was. However, similar to concurrent placebo effects, remembered placebo effects were strongly associated with expected pain levels that occurred just after conditioning. Taken together, these results suggest that magnitudes of placebo effect are dependent on multiple factors, including conditioning, expectancy, and whether analgesia is assessed concurrently or retrospectively.  
  Call Number Serial 240  
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Author (up) Staats, P.; Hekmat, H.; Staats, A. file  url
  Title Suggestion/placebo effects on pain: negative as well as positive Type
  Year 1998 Publication Journal of Pain and Symptom Management Abbreviated Journal J Pain Symptom Manage  
  Volume 15 Issue 4 Pages 235-243  
  Keywords Adolescent; Adult; Female; Humans; Male; Pain/*drug therapy; *Placebo Effect; *Suggestion; Treatment Outcome  
  Abstract This study explores the effect of positive and negative placebo suggestions on pain induced by hand exposures to ice water. Thirty-six participants were randomly assigned to one of the following interventions: (a) positive placebo suggestion, (b) negative placebo suggestion, and (c) control. The positive placebo-suggestion participants were given favorable messages about the beneficial effects of ice-water hand immersion. The negative placebo-suggestion group was given messages depicting the negative effects of exposure to ice water. The control groups were given neutral messages about exposure to ice water. Participants rehearsed the messages and focused on them during their second hand exposures. Results indicate that both the positive and negative placebo-suggestion interventions significantly altered participants' pain threshold, pain tolerance, and pain endurance. Participants exposed to a positive placebo condition tolerated pain better than a neutral condition. Participants exposed to a negative placebo did not tolerate pain as well as participants with a neutral condition.  
  Call Number Serial 242  
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Author (up) Stewart-Williams, S.; Podd, J. file  url
doi  openurl
  Title The placebo effect: dissolving the expectancy versus conditioning debate Type Journal Article
  Year 2004 Publication Psychological Bulletin Abbreviated Journal Psychol Bull  
  Volume 130 Issue 2 Pages 324-340  
  Keywords Cognition; *Conditioning (Psychology); Humans; *Placebo Effect  
  Abstract The authors review the literature on the 2 main models of the placebo effect: expectancy theory and classical conditioning. A path is suggested to dissolving the theoretical impasse that has long plagued this issue. The key is to make a clear distinction between 2 questions: What factors shape placebo effects? and What learning mediates the placebo effect? The reviewed literature suggests that classical conditioning procedures are one shaping factor but that verbal information can also shape placebo effects. The literature also suggests that conditioning procedures and other sources of information sometimes shape conscious expectancies and that these expectancies mediate some placebo effects; however, in other cases conditioning procedures appear to shape placebo effects that are not mediated by conscious cognition.  
  Call Number Serial 243  
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Author (up) Wall, P.D. file  url
  Title The placebo effect: an unpopular topic Type Journal Article
  Year 1992 Publication Pain Abbreviated Journal Pain  
  Volume 51 Issue 1 Pages 1-3  
  Keywords Conditioning, Classical; Humans; Placebo Effect; *Placebos; Research Design  
  Call Number Serial 241  
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